It is known to sever rotating pipes normal to the axis by means of metal-cutting "turning" (plunge cutting), with the aid of a cutting tool advanced transversely relative to the workpiece axis. A typical example is cutting performed on a lathe. In such an operation, a long chip or shaving is produced, depending upon the cutting depth. Means exist for breaking such a chip. Difficulties can be encountered with alloy materials. The chips harden and may have sharp edges, which present the danger of injury. There are limits to this method, which in itself is simple, if the workpieces are quite long--that is, for instance if parts are to be cut off from long, rolled rounded-profiled elements. Long workpieces of this kind are frequently not capable of rotating at a speed such as is required for an economically favorable cutting speed. Rounded-profiled elements of small diameter must furthermore be well guided, for instance in sheathing pipes; but experience has shown that sheathing is associated with a high noise level.
In the case of workpiece at high temperature, such as those in a glowing red-hot state, the above method is intrinsically impossible. Severing has then been performed using high-powered saws. This latter method has been developed to a state of technical perfection, but extremely high noise levels are unavoidable.
When brief cutting times are critical, which is particularly important in the case of red-hot workpieces, a high cutting speed and small tooth pitch must be selected. This results in a high frequency of cutting operations, thus causing high-frequency acoustical oscillations which may have their source in either the saw blade or the pipe itself or both. Glowing chips are also thrown off, and wide ridges are formed at the cutting site; in fact, the pipe may even become completely closed at its end. These disadvantages, and particularly the great environmental stress, make it urgently necessary to provide an improved solution to the problem.